Technology for presenting graphical information to an observer by irradiating laser light onto a screen or ceiling is described in patent publications 1 and 2 below. With this technology it is possible to render an arbitrary graphic (for example a symbol or letter) by scanning laser light using galvano mirrors having two axes.
However, with these technologies there is a problem in that it is difficult to render a large graphic that is larger than the size of the physical object that is being irradiated (for example, a screen).
On the other hand, so-called versa-writer technology is known (refer to patent publication 3 below). This technology presents graphical information to an observer using an after-image effect, by moving a light beam at high speed in a given direction.
However, with a versa-writer a light source itself passes along a given path. This means that if power feed to the light source is considered, there is a considerable restriction in the path the light source follows, and as a result there is a restriction in the depiction that can be carried out with a versa-writer. Also, with a versa-writer, it is theoretically difficult to carry out depiction on an arbitrary object without a light source.